PLATE LV. 



PAGE 



Figs. 1-4. Mulinia lateralis ( Say) 194 



1. Interior of left valve. Wailes Bluff. X 1% 



2. Exterior of right valve. 



3. Interior of same. 



4. Exterior of left valve. 



Figs. 5-8. Rangia cuneata (Gray) 195 



5. Interior of right valve. Potomac shore between Float and Poplar 



Hill creeks. 



6. Exterior of left valve. 



7. Interior of left valve. 



8. Exterior of right valve. 



Figs. 9, 10. Essis directus (Conrad) 196 



9. Interior of left valve. Portland, Maine. 

 10. Exterior of same. 



